#include<graphics.h>
#include<conio.h>
#define High 480
#define Width 640
#deefine BallNum 5

int main()
{
	float ball_x[BallNum],ball_y[BallNum];
	float ball_vx[BallNum],ball_vy[BallNum]; 
	float radius;
	int i;
	radius = 20;
	
		for(i = 0;i<BallNun;i++)
	{
		ball_x[i] = (i+2) * radius * 3;
		ball_y[i] = High/2;
		ball_vx[i] = 1;
		ball_vy[i] = 1;
			
}
initgraph(Width,High);
BeginBatchDraw();

while(1)
{
	setcolor(BLACK);
	setfillcolor(BLACK);
	for(i=0;i<BallNum;i++)
	fillcircle(ball_x[i],ball_y[i],radius);
	
	for(i=0;i<BallNum;i++)
	{
		ball_x[i] = ball_x[i] + ball_vx[i];
		ball_y[i] = ball_y[i] + ball_vy[i];
	}
	
	for(i=0;i<BallNum;i++)
	{
		if((ball_x[i]<=radius)||(ball_x[i]>=Width-radius))
	    	ball_vx[i] = -ball_vx[i];
	    if((ball_y[i]<=radius)||(ball_y[i]>=High-radius))
	        ball_vy[i] = -ball_vy[i];	 
	}
	setcolor(YELLOW);
	setfillcolor(GREEN);
	for(i=0;i<BallNum;i++)
	    fillcircle(ball_x[i],ball_y[i],radius);
	    
	    FlushBatchDraw();
	    
	    sleep;
}
EndBatchDraw();
closegraph();
return 0;
}

